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101.
102.
奥里诺科河是亚马逊河上一条光涌的逆流,更是一段有关虔诚的传教士和印第安土著人的古老故事。  相似文献   
103.
In technological approaches to prehistoric industries, there is currently a renewed interest in the transformation of osseous materials. This approach requires the construction of a technical reference base of manufacturing stigmata, as well as of the procedures and methods used to produce tool blanks.One of the better known processes for the production of blanks in the Upper Palaeolithic is extraction by a double longitudinal groove, observed only in the Gravettian. Aurignacian artefacts indicate that during this period blanks were obtained through a procedure of longitudinal fracturing (splitting) or diffuse percussion fracturing. The manner of implementing these procedures is, however, still poorly known.In order to better characterise this stage in the manufacturing of blanks for antler points, we conducted an experimental study. Based on a thorough analysis of the Spanish archaeological materials, we tested the procedure of fracturing by indirect percussion on deer antler. The results provide new criteria for the identification of blanks and their manufacturing processes. They also emphasize the possibility of predetermining the size of the blank and, consequently, the size of future projectile point.  相似文献   
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We report the results of a test excavation of deposits in a limestone cave sub-chamber located beneath the main chamber of Liang Bua, Flores, Indonesia; the discovery site of the small hominin species, Homo floresiensis. Well-preserved remains of extinct Pleistocene fauna and stone artefacts have previously been identified on the surface of a sediment cone within the sub-chamber. Our excavation of the deposits, at the base of the sediment cone in the sub-chamber (to 130 cm depth) yielded only a few fragmentary bones of extant fauna. Uranium/Thorium (U-series or U/Th) dating of soda straw stalactites excavated from 20 to 130 cm in depth demonstrates that the excavated sediments were deposited during the Holocene. Red Thermoluminescence (TL) dating of the sediments at the base of the excavation (130 cm depth) indicates these sediments were last exposed to sunlight at 84 ± 15 ka (thousand years), similar to red TL ages of cave sediments from the main chamber. Together, these results indicate that the surface faunal remains, which are morphologically analogous to Pleistocene finds from the main chamber excavations, were transported to the sub-chamber relatively recently from the main chamber of Liang Bua and probably originated from conglomerate deposits at the rear of the cave and from deposits around the front entrance. There is no evidence for hominin occupation of the sub-chamber, instead it seems to have acted as a sink for cultural materials and fossil remains transported from the surface via sinkholes. Despite the small number of finds from the test excavation, it is possible that more extensive excavations may yield additional transported cultural and faunal evidence at greater depths.  相似文献   
106.
Le classement des differentes paroles en Gn 1 selon des formules-cadre a permis à Paul Beauchamp de faire la brillante proposition que l'on sait sur la composition littéraire de ce texte. La question reste cependant posée de savoir combien de paroles de commandement se lisent en fait en Gn 1, le chiffre dix ne pouvant être obtenu sans quelque artifice discutable. Si l'on s'en tient aux données les plus obvies du texte, on peut alors risquer l'étude de sa structure littéraire á partir des recurrences verbales, lesquelles permettent, en exploitant plusieurs remarques de Paul Beauchamp, mais aussi en mettant à profit les anciennes distinctions entre opus distinctionis et opus ornatus, ou entre contenants et contenus, de découvrir les structures littéraires de Gn 1, 3-31, mais aussi de 1, 1-2 et 2, 1-4a, ainsi que des rapports structurels entre ces derniers et l'ensemble de 1, 3-31.  相似文献   
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Lithic debris derived from knapping and used tools can be assimilated to simple sedimentary particles that may undergo size sorting when exposed to geomorphic processes such as streamflow or overland flow. Sorting can be identified by comparing the size distribution of archaeological assemblages to that of experimental core reduction sequences. A new database including different types of raw material (mainly flint and quartzite) and Palaeolithic debitage (blade, Levallois, discoid, on anvil, and shaping) has been built for this purpose. Palaeoeskimo data have also been added to illustrate microlithic industries. For all the debitages and raw materials, the particle size of knapping products >2 mm in width fits with a power-law distribution and shows only minor fluctuations, the range of which is always <15% between experiments (all steps of the chaîne opératoire included up to the final tool). A lithic assemblage derived from block/core knapping or blank/preform production will display a particle size distribution close to the experimental distributions if not subsequently modified. Modifications may originate either from sedimentary processes or from anthropogenic factors. To help distinguishing amongst these, data on the impact of both water flows on sedimentary particles or experimental assemblages, and anthropogenic processes such as importation-exportation (of core, preforms or finished tools) or uneven spatial distribution of the different steps in core reduction and tool production within a site, are reviewed. By contrast to anthropogenic modifications, sedimentary processes are generally typified by strong impoverishment in or selective accumulation of fine-grained (<10 mm) artefacts together with a low intra-site variability (spatial homogenization) or a downslope size trend. Archaeological case studies taken from French Palaeolithic site are then detailed. Evidence for lithic redistribution implies that care should be taken in archaeological site analysis since sorting may impact significantly the initial techno-typological balance of the assemblage.  相似文献   
109.
The rapid and unpredictable changes in the Middle East collectively known as the “Arab Spring” are posing tremendous challenges to U.S. policy formation and action. This article will explore and evaluate evolving U.S. policy in the Middle East and its potential implications. There has always been a tension in American foreign policy between pursuing American “values” (foreign policy idealism) and protecting American “interests” (foreign policy realism). For decades, the United States has sought to “make the world safe for democracy,” while at the same time often supporting repressive, nondemocratic regimes because of national security or economic self‐interest. The tension between these two fundamentally distinct policy orientations has become even more pronounced as the United States tries to respond to the Arab Spring uprisings. Why did the United States actively support the rebels in Libya but not the protestors in Syria or Bahrain? Is there an emerging, coherent “Obama Doctrine” on intervention in Arab countries, or was Libya just a “one‐off” event? These are some of the questions that this article will attempt to answer.  相似文献   
110.
The Minjiang River terrace along the Longmen Shan fault zone near Wenchuan, at the eastern margin of the Tibetan Plateau, China, provides archives for tectonic activity and quaternary climate change. However, previous studies were not able to provide ages older than 100 ka due to the limitations of dating material or/and methods applied to date the fluvial sediments. In this study, we used the ESR signal of the Ti-Li center in quartz to obtain the ages of four higher terraces (T3–T6). According to the results, the terraces T3 to T6 were formed at 64±19 ka, 101±15 ka, 153±33 ka, and 423±115 ka, respectively. Combined with previous studies, these results indicate that the formations of all terraces correspond to glacial/interglacial transition periods, such as, T1-T5 being correlated to MIS2/1, MIS4/3, MIS5d/5c, and MIS6/5e respectively, while T6 probably to MIS12/11. According to these data, it is found that the average incision rate was significantly higher over the last 150 ka than that previous 100 ka (250 to 150 ka). As both tectonics and climate have affected the formation of these terraces, in addition to the overall uplifting of Tibetan Plateau, the regional uplift due to isostasy would be an additional tectonic factor in the formation of river terraces in the eastern margin of Tibetan plateau.  相似文献   
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